1. Field of the Invention
The present invention relates to a recording method for a recording medium, such as an optical disc, and a recorder.
2. Description of the Related Art
Various apparatuses that record data by irradiating a medium, such as a disc, with laser beam are realized. For example, there is an apparatus that records the data by irradiating a disc of a compact disc (CD) type and a disc called a Digital Versatile Disc (DVD) with the laser beam modulated using the data to be recorded.
To record data using the laser beam, for example, as described in Japanese Patent Laid-Open No. 2000-251254, the laser beam power, specifically, recording power or erasing power must be set for an adequate value. Accordingly, usually, in a recorder, discrimination operation of the optimum laser power called OPC (optimum power control) is performed. This OPC operation performs trial writing by irradiating a trial write area (test area) prepared on the disc with the laser beam varying the laser power and discriminates the optimum laser power by monitoring the qualities (for example, jitter information, error rate information, and asymmetry information) of the reproduction information on the trial write portion. The OPC operation enables recording operation using the optimum laser power at recording.
Moreover, as trial write operation, as described in the DVD-RAM standard, not only the optimization of the recording power by the OPC but also the suitability of recording pulse width is performed to suppress the effects of the distortion of an optical spot on an optical disc and the thermal interference of a recording mark and form a recording mark of higher quality. The trial writing is performed varying recording pulse width in accordance with a combination of the recording mark and space width and the operation that discriminates the optimum recording pulse width is performed by monitoring the qualities (for example, jitter information, error rate information, and asymmetry information) of the reproduction information on the trial write portion.
If there is a defective portion, such as a scratch or dirt, in the trial write area, the signal quality monitored in the OPC operation will be affected by the scratch. This causes a fault in the operation that discriminates the optimum laser power according to the OPC operation and no adequate discrimination operation will be able to be executed. Accordingly, there is a method for avoiding a defective area in the trial write area and selecting an area to be used with reference to the trial write area management information.
This method checks the defective area in the beginning of use and registers the defective portion, such as the scratch or dirt, as the trial write area management information. Further, the scratch or dirt adheres to an optical disc when it is used and a new defective area may occur. On this occasion, when the quality of the reproduction information on the trial write operation is checked, a new defective portion is detected, but the reproduction information recorded in the defective portion is not used. In this case, however, the information on recording conditions recorded in the defective portion is lost and adequate discrimination operation will be disabled.
Moreover, position information on the detected defective portion must be added to the trial write area management information so that the adequate discrimination operation will be enabled at next trial writing. In this case, the trial write area management information will be additionally recorded or rewritten. Consequently, however, time is consumed at that rate and the operation including data recording is delayed, thereby sacrificing convenience as a recorder.
To solve the above problem, in Japanese Patent Laid-Open No. 2000-105924, a method for detecting a defective area during trial write operation and performing the recording again in another area under the same conditions as an area in which the defective area was detected is proposed. As a defective area detection method, as described in paragraph 52 of the same Japanese Patent Publication, the defective area is detected by decreasing a level of a reproduction signal RF using the reproduction signal RF in the space portion behind a recording area (mark portion) in which trial write information was recorded.